Hybrid Post-Quantum Password Authenticated Key Exchange

This document describes the CPaceOQUAKE+ protocol, a hybrid asymmetric password-authenticated key exchange (aPAKE) that supports mutual authentication in a client-server setting secure against quantum-capable attackers. CPaceOQUAKE+ is the result of a KEM-based transformation from the hybrid symmetric PAKE protocol called CPaceOQUAKE that is also described in this document. This document recommends configurations for CPaceOQUAKE+.